Known machines or apparatuses of this type are of the kind described in U.S. Pat. No. 4,845,924 and U.S. Pat. No. 5,459,979. In brief, these are high speed packaging machines, comprising a drum provided with radial pockets with dimensions that are suitable for the product to be packaged, inside which the stacks of product to be packaged are inserted in rapid succession, with the simultaneous interposition of one blank plastic film, so as to obtain the complete wrapping of each stack, completed by welding applied on the film to obtain a closed packaging.
In machines of this kind, due to the high operation speed that is required to ensure suitable productivity, it is very complex to compress the stack, keep its correct geometry and carry out the insertion inside the pockets of the drum without causing deformations or faults in the wrapping by the film. In particular, but not exclusively, it is difficult, if not impossible, to keep control of the position of the film and of the compression in the radial direction of insertion during the wrapping step when the speed increases beyond a certain limit, causing defects in the package which, in any case, can occur also when the speed is kept below said limit.